ES's are currently being studied as a means of reducing errors in defining requirements and communicating them to the team responsible for implementing designs. An IcoSim ES unambiguously describes the functional performance of the system element that it simulates, and forms the functional requirements specification for detailed design. A HW design is simulated for each ES with sufficient fidelity to execute the SW object code developed to implement the specified requirements. The simulated HW running the SW object code, referred to as a detailed executable (DE), is plug-in compatible with the ES allowing the SW to be developed and tested in the same system environment in which the ES was developed, using the same system-level test scripts. Triakis' ES concept is described in greater detail in a white paper included as attachment II.